Thermal and dynamic characterization of wet clutch engagement with provision for drive torque

Wet clutches that handle the gearshifts in automatic transmission undergo s evere thermal stresses due to the occurrence of large temperature gradients during engagement. To accurately design wet clutches, better models to sim ulate the engagement process are needed. This,work presents a finite elemen t model for simulating wet clutch engagements. The total friction coefficie nt was used to describe the different lubrication regimes that a wet clutch engagement undergoes. The model also includes provision for drive torque t hat realistically simulates the engine torque of a car. The results of the simulations are successfully verified by comparison with laboratory experim ents on a testrig specially designed to accommodate the drive torque, cover ing a wie range of typical engagements. Excellent agreement between experim ent and simulations is reported in terms of both the dynamics of the engage ment and the thermal characteristics. The results are indicative of the uti lity of the model as a useful engineering tool.